precision mediump float;
 
varying mediump vec2 textureCoordinate;
 
uniform sampler2D inputImageTexture;

uniform float hue;
uniform float value;
uniform float saturation;

vec3 rgb2hsv(vec3 c)
{
	vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
	vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
	vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));

	float d = q.x - min(q.w, q.y);
	float e = 1.0e-10;
	return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
}

vec3 hsv2rgb(vec3 c)
{
	vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
	vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
	return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}



void main(){

 vec3 irgb = texture2D(inputImageTexture, textureCoordinate).rgb;
 vec3 tColor = rgb2hsv(irgb);

 tColor.r = tColor.r * hue;
 tColor.g = tColor.g * saturation;
 tColor.b = tColor.b * value;

  gl_FragColor = vec4(hsv2rgb(tColor), 1.);

}